Beat the softened butter with the sugar until light and fluffy (about 2-3 minutes on high should be enough), add the egg and blend very well. Add the ground walnuts and rum and mix just to combine. Sift the flour with the cornflour (corn starch), baking powder and baking soda and add it to the butter batter in a few additions, beating constantly on low. You should get a lovely soft dough that you need to chill for about 15 minutes in the fridge (put it in the fridge in the bowl you made it in).

Transfer the chilled dough to a lightly floured surface and roll it out to about 5 mm (under ¼") thickness and cut out the desired shapes. Bake them in a preheated oven, at 180˚C (350˚F) for 8-10 minutes, making sure they don't overbake.

Leave the baked cookies to cool down and make the dark chocolate glaze. Melt and temper the chocolate, pour it in a deep and narrow container and dip in the cookies half way up. Let them sit on a wire rack or a silicone mat until the glaze sets. Serve them with tea or strong coffee. Yields 25 cookies.